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    <script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script>
    <title>Title</title>

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<body>
<p id="p_1" style="background-color: red">这是一个段落</p>
<p id="p_2" style="background-color: blue">设置一个段落</p>
<p id="p_3" style="background-color: yellow">设置一个段落</p>

<input id="btn_1" type="button" value="获取css类型"><br/><br/>
<input id="btn_2" type="button" value="设置css"><br/><br/>
<input id="btn_3" type="button" value="设置多个类型"><br/>


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